Method of producing mono-and diglycerides of fatty acids



Patented May 30, 1950 METHOD OF PRODUCING MONO- AND DI- GLYCERIDES F FATTY ACIDS George Barsky, New York, N. Y., assignor to E. F. Drew & Co. Inc., New York, N. Y., a corporation of Delaware No Drawing. Application April 13, 1946, Serial No. 662,085

13 Claims.

The present invention is directed to the production of monoglycerides and di-glycerides of a plurality of fatty acids. More particularly it is directed to a method whereby a glyceride type of oil is treated to recover free fatty acids and to provide a residual composition containing monoand diglycerides of the remaining fatty acids.

In my prior Patent No. 2,182,332, issued December 5, 1939, there was described and claimed a method of treating glyceride oils so as to remove from combination certain of the fatty acids and to replace the same with higher fatty acids. In application Serial No. 640,097, filed January 9, 1946, entitled Method of reconstruction glyceride oils, there has been described an improvement in the treatment of glyceride oils and particularly the cocoanut type of oil, wherein a catalyst is used and a higher efficiency of operation is obtained. Said pending application also describes a, method for removing some of the fatty acids from the glyceride oil without replacement thereof by other fatty acids. The present application is a continuation in part of said pending application and is directed to the process wherein there is removal of fatty acid with-'- out replacement thereof by other fatty acids.

In practicing the present invention there is provided an oil which may be animal or vegetable and which consists essentially of the glycerides.

of a mixture of fatty acids having even numbers of carbon atoms. Various oils are suitable for the present invention, such as the non-drying, semi-drying and drying oils. Usually such oils contain acids having from 6 to 18 carbon atoms or even more. In accordance with the present invention, an oil of this type is mixed with a relatively small amount of boric acid, usually I not over a few percent by weight based upon the oil present. The mixture is heated to a reaction temperature generally at about 250 C. or higher for arelatively long time of at least one hour and usually from 2 hours to 24 hours. The reaction results in liberation of the portion of the fatty acid content of the oil, and preferentially those acids having the lowest number of carbon atoms. Generally there is provided during the reaction period a vacuum so that fatty acids as they are freed are distilled off and thus the equilibrium is continually disturbed. Thereby the reaction progresses with increasing amounts of fatty acids being freed and removed, depending upon the length of time and the temperature of treatment.

In the prior art it has previously been proposed to treat oils with boric acid but the purpose thereof and the results obtained were quite different from the present invention. According to one such prior disclosure, China-wood'oil was heated to about 500 F. and a small amount .of boric acid added thereto so that the latter was absorbed by the oil to cause thickening to take place. The purpose of such a treatment was to thicken the oil without causing gelatinization thereof. Apparently the boric acid provided an acid condition in the oil which accomplished this result.

In another prior art process, hydroxylated oils such as castor oil, were treated with boric acid under such conditions as to cause the boric acid to combine chemically with the oil and specifically the OH group thereof to form. boric acid esters. The purpose of the treatment was to change the characteristics of the oil and to substantially increase the drying properties thereof. The chemical combination of the boric acid with the hydroxyl groups of the oil apparently rendered the oil more capable of absorbing oxygen and thus drying properties were imparted thereto.

The present invention is entirely different from the prior art procedures noted above and seeks to chemically change the constitution of the oils and produce mono-glycerides and diglycerides and mixtures thereof. The invention is more fully illustrated in the following specific examples.

Example 1 203 parts by weight of refined hydrogenated cocoanut oil were used. Approximately twothirds of thiswas put in a kettle and heated to 260 C. with agitation in an atmosphere of carbon dioxide. At that temperature the remaining one-third of the oil, mixed with 12 parts of boric acid, was added continuously over a period of 2 hours. The mixture was then allowed to cool to about C., a vacuum was applied, and the free fatty acids then distilled out, the temperature being allowed to rise upto 280 C. at

.5 mm., the volatile material being collected by 'means of a condenser.

The reaction resulted in a freeing of some of the lower fatty acids of the mixture and esters in the oil, and the application of the vacuum at the stated temperatures caused volatilization of such lower fatty acids and removal thereof from the reaction mass. The product was allowed to cool and was subjected to washing with water, whereby the boric acid was dissolved and any boric acid which might have been combined in the form of esters with the glycerine was removed from combination thereby and put into a water solution. The-boric acid solution was removed and the residual oil refined by procedures common in the vegetable oil industry.

25 parts of distillate were obtained. This had an acid number of 285 and a saponification number of 308. The residual oil had a saponification number of 242 and an acetyl value of 28.1, and consisted essentially of monoglycerides and diglycerides of the higher fatty acids of cocoanut oil. The distillate consisted largely of the lower fatty acids present in the cocoanut oil.

Example 2 9,400 parts of cocoanut oil were mixed with 290 parts of boric acid. The mixture was agitated, a partial vacuum of 10" was applied, and heated slowly while refluxing the vapors back into the kettle. After about two hours the vacuum was increased to 23"27". The temperature was raised to about 290 C. in about 5 hours total time of heating. It was maintained at about this temperature for an additional 8 hours when the reaction was completed.

' The refluxing of the mixture has allowed the lower fatty acids to be removed in the vapor state while the higher fatty acids which might have been released in the process have been returned in order to enter into the reaction. The

About 7,000 parts of ester and over 2,300 parts of distilled lower fatty acids were produced. The refined ester had a setting point of 23.4 C. and an acetyl value of 26.8.

Example 3 203 parts of unhydrogenated cocoanut oil was mixed with 12 pars of boric acid in a reaction kettle and the mixture was heated to a temperature of 270 C. A vacuum was applied and the heating continued over a period of two hours. Distillation of freed fatty acid took place continuously and such acids were removed from the reaction mixture. The temperature gradually rose up to 280 C. at the completion of the opertion.

The boric acid was removed by washing with water and the residual oil was distilled with steam to remove any free fatty acids which might be dissolved in the reaction product. 19.5 parts of the distillate consisting of lower fatty acids of cocoanut oil were obtained.

Example 4 The products of the specific examples set forth above are mixtupres of monoand diglycerides of fatty acids of the higher fatty acids of the original oil. By a further treatment they may be transformed into neutral triglycerides of the mixture of fatt acids. The product of Example 1 was placed in a reaction vessel and heated to a temperature of 280 C. Simultaneously, a high vacuum was applied and the heating was continued for several hours. During the course of the treatment, reactions took place whereby glycerine was freed and was removed by volatilization. The resulting product was a substantially neutral mass of the glycerides of the higher fatty acids contained in cocoanut oil. It had a relatively high melting point and was a hard butter such as is used in candy making and the like.

Example 5 200 parts of refined linseed oil were mixed with 12 parts of boric acid and placed in a re action vessel fitted with a condenser and connected to a source of vacuum. The temperature of the mixture was gradually raised to about 265 C. over a period of 2 hours, and the mixture then held at said temperature for an additional 2.5 hours. During the reaction freed fatty acids were volatilized and condensed. The residual oil was washed with water to remov boric acid and then dried.

15 parts of distillate were obtained, having an acid number of 187, a saponification number of 197, and an iodine number of 152. The residual oil had a saponification number of 191, an acetyl value of 15.1 and an iodine number of 136. The iodine number of the original oil was 175.

Although the invention has been described setting forth several specific examples of the operation thereof, the invention is not limited thereto as numerous variations in the details of the procedure may be made within the spirit of the invention. For instance, the amount of boric acid used in the process may vary to a large extent and it has been found that an amount as little as 0.2% will give the desired result and up to about 10% by weight of the boric acid based upon oil present may be used. If larger amounts are introduced, they do not adversely effect the reaction. In place of boric acid, other substances capable of producing boric acid during the reaction may be used. In the procedure, there is usually removed from 10% to 25% of the fatty acids present in the reacting mixture. However, the process may be 0D- erated so that more or less of such fatty acids 'may be removed. The mixture of fatty acids so produced are useful in industry and may be used as such or may be transformed into such products as esters of glycols for applicationas plasticizers in various industries.

Other oils than cocoanut oil may be treated in accordance with the present invention. Generally oils of the cocoanut type including palm kernel oil and babassu oil may be treated as set forth above. Also, other animal and vegetable oils wherein a pluralit of fatty acids of various carbon contents occur, are amenable to the treatment described herein. Such oils may be drying, non-drying, or semi-drying oils. For instance, linseed oil, soya bean oil and the like may be used. China-wood or other oil that polymerizes readily may be subjected to this process, but care must be taken to avoid excessive polymerization if such is undesirable in the particular product. In the case of semidrying or drying oils, the removal therefrom by the present invention of some of the lower fatty acids often results in an increase in the drying properties of the residual oil.

These and other changes may be made in the details of the invention within the spirit thereof and the invention is therefore to be broadly construed and not to be limited except by the character of the claims appended hereto.

I claim:

1. A method of producing monoand diglycerides of fatty acids which comprises providing a composition consisting essentially of glycerides of a plurality of fatty acids having an even number of carbon atoms and which are higher in fatty acid content than those to be produced, adda composition consisting essentially of glycerides of a plurality of fatty acids having an even number of carbon atoms and which are higher in fatty acid content than those to be produced, adding a small amount of boric acid thereto, heating said mixture to a temperature not less than about 250 C., maintaining said temperature for at least one hour, whereby lower fatty acids are freed from combination, removing said lower acids by distillation during said heating, treating the reaction mass with water to dissolve said boric acid, and removing said solution.

3. A method of producing monoand dislycerides of fatty acids which comprises providing a composition consisting essentially of glycerides of a plurality of fatty acids having an even num-- ber of carbon atoms and which are higher in fatty acid content than those to be produced, adding a small amount of boric acid thereto, heating said mixture to a temperature not less than about 250 C., maintaining said temperature for at least one hour, whereby lower fatty acids are freed from combination, removing said lower acids by distillation during said heating, adding a lower alcohol to form a boric ester, and distilling the latter from the reaction mass.

4. A method of producing monoand diglycerides of fatty acids which comprises providing a composition consisting essentially of glycerides of a plurality of fatty acids having an even number of carbon atoms and which are higher in fatty acid content than those to be produced, adding a small amount of boric acid thereto, heating said mixture to a temperature not less than about 250 C., maintaining said temperature for at least one hour, whereby lower fatty acids are freed from combination, removing said lower acids by distillation during said heating, adding methyl alcohol to form methyl borate, and distilling said borate from the reaction mass.

5. A method of producing monoand diglycerides of fatty acids which comprises providing a composition consisting essentially of glycerides of a plurality of fatty acids having an even number of carbon atoms and which are higher in fatty acid content than those to be produced, adding a small amount of boric acid thereto, heating said mixture to a temperature not less than about 250 C., maintaining said temperature for at least one hour, whereby lower fatty acids are freed from combination, removing said lower acids by distillation during said heating, and steam distilling the reaction mass to remove residual free fatty acids therefrom.

6. A method of producing monoand diglycerides of fatty acids which comprises providing a composition consisting essentially of glycerides of a plurality of fatty acids having an even number of carbon atoms and which are higher in fatty acid content than those to be produced, adding a small amount of boric acid thereto, heating said mixture to a temperature not less than about 250 C., maintaining said temperature for at least one hour, subjecting said mixture to a vacuum during the period of treatment, whereby lower 6 fatty acids are freed from combination, removing said lower acids by distillation during said heating.

7. A method of producing monoand diglycerides of fatty acids which comprises providing a composition consisting essentially of glycerides of a plurality of fatty acids having an even numberof carbon atoms and which are higher in fatty acid content than those to be produced, adding a small amount of boricacid thereto, heating said mixture to a temperature of about 250 C. to 300 C., maintaining said temperature for at least one hour, whereby lower fatty acids are freed from combination, removing said lower acids by distillation during said heating.

8. A method of producing monoand diglycerides of fatty acids which comprises providing a composition consisting essentially of glycerides of a plurality of fatty acids having an even number of carbon atoms and which are higher in fatty acid content than those to be produced, adding a small amount of boric acid thereto, heating said mixture to a temperature not less than about 250 C., maintaining said temperature for from 2 to 10 hours, whereby lower fatty acids are freed from combination, removing said lower acids by distillation during said heating.

9. A method of producing monoand diglycerides of fatty acids which comprises providing a composition consisting essentially of glycerides of a plurality of fatty acids having an even number of carbon atoms and which are higher in fatty acid content than those to be produced, adding a small amount of boric acid thereto, heating said mixture to a temperature not less than about 250 C., maintaining said temperature for at least one hour, subjecting said mixture to a vacuum during the period of treatment, refluxing back into said mixture the higher of the vaporized fatty acids, whereby lower fatty acids are freed from combination, removing said lower acids by distillation during said heating.

10. A method of producing monoand diglycerides of fatty acids which comprises providing a composition consisting essentially of glycerides of a plurality of fatty acids having an even number of carbon atoms and which are higher in fatty acid content than those to be produced, adding a small amount of boric acid thereto, heating said mixture to a temperature not less than about 250 C., maintaining said temperature for at least one hour, whereby lower fatty acids are freed from combination, removing said lower acids by distillation during said heating, removing the catalyst from the reaction mass, and then heating the same under a vacuum to remove glycerine from said mass.

11. A method of producing monoand diglycerides of fatty acids which comprises providing a composition consisting essentially of higher glycerides than those to be produced of a plurality of fatty acids having from 6 to 18 carbon atoms, adding a small amount of boric acid thereto, heating said mixture to a sufflciently high temperature to free lower fatty acids, maintaining said temperature for a sufllcient time to cause distillation of said free fatty acids.

12. A method of producing monoand diglycerides of fatty acids which comprises providing a composition consisting essentially of higher glycerides than those to be produced of a plurality of fatty acids having from 6 to 18 carbon atoms, adding a small amount of boric acid thereto, heating said mixture to a sufliciently high temperature to free lower fatty acids. maintaining said temperature for a sufllcient time under a vacuum to cause distillation of said free fatty acids.

13. A method of producing monoand diglycerides of fatty acids which comprises providing 5 a composition consisting essentially of higher glycerides than those to be produced of a plurality of fatty acids having from 6 to 18 carbon atoms, adding a small amount of boric acid thereto, heating said mixture to a suiliciently high temperature to free lower fatty acids, maintaining said temperature for a sumcient time to cause distillation-of said free fatty acids, and

thereafter removing said boric acid.

GEORGE BARSKY.

8 REFERENCES crran The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,125,544 Colbeth Aug. 2, 1938 2,378,006 Eckey June 12, 1945 FOREIGN PATENTS Number Country Date 236,928 Great Britain 1926 

1. A METHOD OF PRODUCING MONO- AND DIGLYCERIDES OF FATTY ACIDS WHICH COMPRISES PROVIDING A COMPOSITION CONSISTING ESSENTIALLY OF GLYCERIDES OF A PLURITY OF FATTY ACIDS HAVING AN EVEN NUMBER OF CARBON ATOMS AND WHICH ARE HIGHER IN FATTY ACID CONTENT THAN THOSE TO BE PRODUCED, ADDING A SMALL AMOUNT OF BORIC ACID THERETO, HEATING SAID MIXTURE TO A TEMPERATURE NOT LESS THAN ABOUT 250*C., MAINTAINING SAID TEMPERATURE FOR AT LEAST ONE HOUR, WHEREBY LOWER FATTY ACIDS ARE FREED FROM COMBINATION, REMOVING SAID LOWER ACIDS BY DISTILLATION DURING SAID HEATING. 